Variable-speed device



Mardi 22,192?.

` M. T. WESTON `VARIABLE SPEED DEVICE FUed April 6. 1922. 4A Sheds-Sheet1 /N VENTOR March 22,1927. 1,621,915

y M. T.. WESTON VARIABLE SPEED DEVI CE `Filed April 6. 1922 4Sheets-Sheet 2 w s n W' N f r q.

INIENTOR man Uf/m March 22,1927.

M. T. WESTON VARIABLE SPEED DEVICE Filed lApril e. 1922 4 sheets-Smet sINVENTOR M. T. wEsToN VARIABLE SPEED DEVICE March 22 1927.

Filed April 6 1922 4 Sheets-Sheet 4 NVENTOR dem um. IW.. I m 1 m, m w uwam HH... ..H..-w....` d u* /m v rf /xlN 1 w 1N .//vm///// 1".: N ...PQ

Patented Mar. 22, 1927.

UNITED 'TST i y l,621,9-155 PATE-NT orsi-ien.

MLTN "T. WESTON, OF NEW' TYORKfN. Y.

Application filed April S, 1922. SerialvNo. 550,041.

4'speed device, easily adaptable tofeither automatic or manual controland `which vvill he reliable and sensitive in operation and relativelyinezfrpensive in construction. .Other objectsand advantages Will Aappearin the following specifications and are clearly shown in theaccompanying drawings in which the same Anumeral refers to similarparts-inrall the views.,

Figl, is-a .longitudinal cross section on a line AD-D of .Fig.-2.

F ig..2,1is.a plan vieivotmydevice.

IFig. 3, is a transverse sectional vievv on a line fir-A of vFigs. land2.

F ig. 4l, is -a detail cross sectional view taken substantially on -aline B--B ot Flig. Land shows the jaw clutch operator.

F ig. 5, is a transverse sectional v-ievvY -on a line G-C-of Fig. l.

Fig. 6, is a partial sectional view sho-Wing a slightliydifterentarraugementiot the gears shown in Fig. l.

Fig. 7, is a partial transverse lsectional vieiv showing a modificationof the Amethod ofcontrol illustrated -in Fig. 8, isa diagrammatic viewillustrating one applicationot `my device.

In `carrying-out my invention, l provide a base l, onl Whichlare mountedthe outboard bearingstand2, and the mainfbearingstands 3. A drum rorhousing 4, comprising a cylindrical shell la `with-enddiscs ib and lli-,iis revol uibly mounted xin the main `bearing stands-3, by meansolthctrunnionsfl and 5C. shown integral with their respective Vend discs 1lband llc. Projecting `through Ethe trunnion 5?, and concentric therewith,is la driving shatt 6, having its router end supported in the outboardbearing stand 2. .A belt pulley 7, is shown tixed to the driving shaft`6, between the outboard bearing stand yand the adjacent mainbearingstand A driven shaft 8 projects through the `trunnion o, and isconcentric therewith. It will be understood `that the'drivii'ig sha'lit(i, and the drivensha'tt 8, are revolvable in ithe respective trunnions5ba-nd 5c, and that the drum or housing Ll, is also revolvable on thetrun rions 5" and-52m the main bearing stands 3, independent of the saiddriving and driven sha-tts.

y Within Vthe revolvable housing 2l, on the inwardly projecting end oithey driving shaft 6, is a pinion) and on the adjacent end `of thedriven shaft Sis afgear l0, as `clearly shown in F ig. '1. Spaced at adistance 'from the driving shaft 6 and thedriven shaft-8, andparallelto'them, are auxiliary sha/tts il with theirendsjournalled in the endv`discs 2lb and 4to. 'On these shafts l1 are -i'in'edft'he gears 12,meshing with pinion 9 onthe drivlng shaft Gand also the pinions 13inrlmesh VWith gear l on the dri-ven shaft 8. There are preferably 3sets of shafts 11,1gears312f and 4pinions 13, equally spaced to give abalanced construction as shown in Fig. 5. It will be obvious that whenthe revolvabli-x housing 4 is held, in a manner to Abe describedhereinafter, so as not to revolve While the shaft'-is being driven'bythe pul ley 7, the pinion 9 -Will impart rotation 'tol the .gears l2,resulting lin the gear l() being driven by the .pinions A13. The drivenshaft 8 will consequently be revolved and at a lower speed than thedrivingr shaft I6, but'this speed Will ybe constant.v with lrespect ltothe said driving shaft 6. Therefore, While Ithe housing 4 is heldagainst rotation, the device-constitutes a simple speed reducer which isdesirable in many eases Vas it 4ipermits nthe design of the device `forthe approximate speed desired and obviat'es the necessity of usingadditional or extraneous speed reducing apparatus. i

`In cases Where it is lnot necessary tor desirable to Yreduce the speed`of the I driven shaft. 8, with respect to the driving'shatt G, thearrangement of gears show-n in Fig. 6 may be iused. In this view, .Ishow gears le of 4equal diameter, on. the `adjacent -end's `ot thedriving shaft v6 and the drivenshaft 8, meshing with .-pinions loff-equal diameter, mounted on the auxiliary shafts :l1 which arejournalled .in the housing 4t. it vvill be clear that in thisconstruction the driven shaft 8 -Will revolve at the same speed as Ydriving shaft 6 so longas the lhousing l lis held.

However, -When the housing l is not held against rotation and is Jfreeto revel-'veen its trunn-ions 5l and 5C, the gearing vbecomes epicyclicand, owing-to the resistance ofthe drivenshaft 8 which lis the zloadshaft-t, `the gear 10 fbecomes substantially -iixed and :pinions 13 Willtravel around said gear l0, carrying the housing 4 with them. It will beclear that the housing 4 will revolve at its maximum speed with respectto driving shaft 6 when the driven shaft 8 is held fixed by its load.Conversely, the driven shaft 8 will revolve at its maximum speed withrespect to the driving shaft 6 when the revolvable housing 4 is heldstationary. From the foregoing it will be seen that the speed of thedriven shaft 8 increases from zero revolutions when the housing 4 isfree to revolve, to its maximum speed when the said housing 4 is heldstationary. Therefore, the speed of the driven shaft 8 varies inverselyas the speed of Ithe revolvable housing 4. It is essentially the objectof my invention to control the speed of rotation of the revolvablehousing 4, thereby attaining a speed for the driven shaft 8, whichvaries from its normal speed with respect to the driving shaft 6, and tomaintainV that speed or to vary it at i' will, either manually orautomatically. It

is this feature, I believe to be broadly new and which will now bedescribed.

When the housing 4 is free to revolve as explained above, the drivenshaft 8 and the machine to which it is connected, are stationary, whilethe driving shaft 6 is running at full operating speed. When it isdesired ltol start the machine to which my device is connected, thehousing 4 is gradually brought to rest inthe following manner: A brakeband 16, of the usual construction, surrounds 'the cylindrical shell 4,of the housing 4 but is normally free as shown in Figs. 1 and 5. One endof this brake band 16 is fixed to the base 1, at 17, while the other endis attached to the fulcrum lever 18, mounted in lugs 19, on the base 1.Moving the fulcrum lever 18 in the direction indicated in Fig. 5 bringsthe'bralre band 16 into circumferential engagement with the revolvablehousing 4 and by exerting increasing pressure on the fulcrum lever 18,the housing 4 will be brought gradually to rest while simultaneously thedriven shaft 8 and its machine, will be brought gradually to its fullworking speed. This arrangement of the brake band 'there fore, performsthe function of a friction clutch but in a much more advantageous manneras it does not require additional room and its cost is relatively smallas conipared to the apparatus it replaces. As long as the housing 4 isgripped by the brake band 16, the machine will he driven at a constant`speed with respect to the driving shaft 6.

l/Vhen it becomes desirable or necessary to vary the speed of themachine, the lever 20 is moved from the position shown in dotted linesin Fig. 1. to the position shown in full lines which brings the controldevice for the housing 4 into operation. The brake band 16 is thenreleased and the control device now governs the rotation of the housing4 as follows: Y

A gear 21, shown in the drawings as a worm wheel, is mounted on theextended end of the trunnion 5c and the said trunnion is revolvable inthe said gear 21 while the brake band 16 is in use, as previouslydescribed. Moving the lever 20, above mentioned, brings a sliding jawclutch member 22, splined on the trunnion 5c, into locking engagementwith the jaws on the face of the hub ofthe gear 21, said gear 21 thenbeing positively revolvable with the housing 4. The method of moving thesliding jaw clutch member 22 is shown clearly in Fig. 4. The lever 20 ismounted on the outer end of the rocker shaft 28, journalled in the gearcasing 24. A forked lever 25, secured to the rocker shaft 28, engagesthe sliding jaw clutch member 22 in the usual manner to impart axialmovement to it when the ,lever 20 is moved as described above. Referringparticularly to Fig. 3, I show the worm wheel 21 in engagement with aworm 26, mounted on and secured to a shaft 27 which is carefully alignedin ball bearings 28, in order to minimize the resistance to the rotationof said shaft and also to take care of the thrust of the worm 26. Thefunction of the worm wheel 21 and its mating worm 26 is to restrain andgovern the revolution of housing 4 and to offer substantial and positiveresistance to 'the normal tendency of said housing` to revolve in orderto transmit the required power from the driving to the driven shaft. Inorder to accomplish this result I choose a worm 26 with a thread anglewhose tangent is slightly greater than the coefficient of fric-- tion.This permits the worm 26 to be driven by the worm wheel 21, but withvery little power both on account of design and because of its loweiiiciency. It is therefore obvious that very little restraining orholding effort applied to the shaft 27, will retard the revolution ofsame or stop it altogether. I apply and control this restraining orholding effort in the form of a friction brake, preferably of themultiple disc type, which however, must not be confused with a multipledisc clutch of similar design as its function is somewhat different. Ingeneral it simply resists and does not grip.

This friction brake consists essentially of a spider 29, mounted on andsecured to worm shaft 27, said spider being splined on its outerperiphery to receive a plurality of discs 30, alternating with a similarnumber of discs 31, in engagement with the splines on the interior ofthe cylindrical extension 24, of the gear case 24. The discs 30 rotatewith the spider 29 but discs 31 are held against rotation bythecylindrical extension 241k All of the discs are movable axially. Apressure plate 32, carried by the spider 29, is provided with pins whichproject through the face of said spider and are engaged by the radiallyextending arms of the bell cranks neen-ere 34,imountedin flugsonthe"tace ofthe spider 29. The-'horizontal arms oit the bell cranks 34, aresubstantially parallelfto the-shaft 27 and are weightedat'theirfoutereiids as indicated at 35. The outer ends of these bellcranlrsl-l are alsoiconnected. to the links 36, saidliiikshavingl theiro-ppositeends pivoted on the axially movable collar?. A compressionspring'tiis interposed between the collar Sfand the hub of the spider 29to restrain 4the axial movement oi said collar. lVhen lthe worin shaft27 revolves,centriii ugal torce causes the weighted ends oi thebell'cranlts'34to-iy outwardbut this movement is resisted -by the actionof the coinpression spring 38. rlhe amount ot movementyisthereforedependent upon the speed of'rotation ol the shaft 27. `Anyoutward movement of the weighted `arms oi' the bell cran-ks 34 bringsthe `radially extending` arms into `engagement with the pins 33 to torcethe pressure-'plate 32 againstI the discs 30 vand 311 increasing thefriction between them lby compression and thus causing greaterresistance `to befoilered to the rotation i' vthe Aworm shaft 27. Altwill be evidentwthata point willbe `reached where the retarding'actionot the discs will just balance -tlieturiiiiigeil'ortexerted bythe wormwheel and worin and the resultant speed will be maintained'as long`asthe conditions remain unchanged. It may, however, b necessary to varythe speed automatically and this is accomplished by employing anadjustable axially movable pressure plate 39, against which the discsand 3l abut instead ot against the customary fixed surface. It will beseen lthat itthe adjustable pressure lplate 39 ris moved toward thediscs 30 and 31, a lower speed ot' rotation ofthe shaft l27 will causesuiiicient compression ot' thesaid discs to retard the rotation of thesaid' sha-ft 27. It', on the other hand, the adjustable pressure plate39 is moved away :trom the discs 30 and 31,-a higher `speedof rotationof the shaft 27 will be necessary to cause sufficient pressure toyretard the revolution of saidshaft. To move the pressure pla-te 39axially, I providefthe said pressure plate with a relatively long` hub39 which is threaded on the outside to receive the threaded bore of asmall worm Wheel 40. yEhe hub 39 is slidable axially in the smooth boreof AtheV retaining plate 41, and in the smooth bore ot' the hub of theend cap 42. The pressure ,plate 39 is thus supported iiidependent ot'the shaft 2T which passes through the relatively :large bore in the hubV39a -with-out coming in Contact with it. The worm wheel 40 is rotatedby the mating,` worm 43, mounted on a sha-tt 44, ouriialled transverselyin the end cap 42. On the outer end of the shaft 44, I ave shown adirect connected motor 45, by means of which said shaft 44 maybeautomatically site direction will move the :pressure plate 239 awayiroinithe said-discs and thus permit a higher speed of rotationof `the-sliatt27. The variationinthe sneed ofi-the worin-sha'it 2 will cause acorresponding` variation yin the permissible revolution of the housing 4and a consequent =variation l'in the speed ot the driven shaft 8, all asclearly described in the foregoing. i

in Fig'. 8, I showdiagramiuatically, a speciiic application of mydeviceto onset-sewL eral units ot' a paper nia-hing; machine. 4"But I do notWish to coniine-my inveiitionrtothis particular field astliere are man y`other requirements tor a device ot this character. ln Fig. 8, apaitialdryer unit is illustrated. My apparatus is*directconnected to oneot the shafts 46, ot the drying unit by means ot the flexible coupling47, showiiiin Fig. ll. The web of paper 48 is deflected ii-oni itsnormal straight path from one-ofthe drying rollsto another by the roller49, extending across the entire face ot the web. IRoller 49 is supportedby the swinging arms `50 mounted on a pivotal shaft 51, carried v(in thetraine of the paper machine, 'Variation of the path-of the'web 48 at thepoint of contact with the roller 49 beyond `certain liniits indicated bydotted lines, will throw `in a reversing switch 52 and cause the motor45 to lrevolve in a direction-tocorrect the tendency of the web 48, -tobecome itoo loose Fig. 7, I show a variable speed motor mdirectlyconnected to the worin lsha'itt 27. It is obvious that if a rlieostat orelectric controller is substituted for the reversingl switch 52 iii Fig.8, the variable speed motor 433, will be controlled in the same mannerthe `motor 45 in Fig. 2.

t will be understood that the gear case 24 contains suiicient oil tokeep the worm wheel 2l, worm 26 and all/ot the controlling y mechanismmounted in said gear case, thoroughly lubricated at all times.Inasiiiuch as there will be avery low unit `pressure on variousyelements of the friction brake, the

lubricating oilv will not be forced from be-a tween the contactingsurfaces as is the case in a friction clutch of similar design. Vifearwill therefore be negligible and uniformity of action will result.

I have shown and described the preferred forms of my invention but oneskilled in the art may design equivalent mechanical means to accomplishthe same results as outlined, which will come within the scope of myinvention. For example, a pulley, driven from some external variablespeed source, pray 7be substituted for the motor 53 in Having thusdescribed my invention, I claim as new and desire tosecure by IlettersPatent: y

l. In a device of the character described, a rotary shaft, a frictiondisk rotating with said shaft, a non-rotatable friction disk cooperatingwith said rotating friction disk,

Y an abutment for limiting the axial displacement of said disks, apressure ring between which and said abutment the friction disks areconfined, means operating by centrifugal force for pressing saidpressure ring against said disks, and means for adjusting said disks andresisting the displacement of said disks under the pressure imparted bysaid centrifugally operated means.

2. In a device of the character described, a rotary shaft, a frictiondisk rotating with said shaft, a non-rotatable friction disk cooperatingwith said rotating friction disk, means Operating by centri"ugal forcefor varying the pressure between said disks, an adjustable abutment forresisting the displacement of `said disks. under the pressure impartedby said centrifugally operated means, a reversible motor, andconnections between said adjustable abutment and said motor.

3. In mechanism of the character described, the combination with arotary shaft, of an axially adjustable abutment, an axially movablepressure"ring, rotatable and nonrotatable friction rings confinedbetween said abutment and pressure ring, a centrifugal governor mountedon said shaft and adapted to press upon said pressure ring, a reversiblemotor, and means operated by said motor for adjusting said abutment.

4. In mechanism of the character described, the combination with arotary shaft,

'of rotatable and non-rotatable friction elements, a reversible motor,and means operated by said motor for varying the frictional resistancebetween said friction elements.

5. In mechanism of the character described, the combination with apower-driven shaft, of a spider secured to said shaft, friction diskssplined to said spider, non-rotatable friction disks alternatelydisposed with respect to the first-mentioned friction disks, an axiallymovable abutment for said friction disks, a motor, means operated bysaid motor for adjusting said abutment, and means controlled by thespeed of said shaft for pressing said friction disks towards saidabutment.

6. In mechanism of the character described, the combination with arotary shaft, of a friction disk splined thereto, a nonrotatablefriction disk, an axially adjustable non-rotatable abutment, a pressurering, said friction disks being axially confined between said abutmentand pressure ring, means depending upon the speed of said shaft forimparting an axial movement to said pressure ring, a reversible motor,and means under the control of said motor for imparting an axialmovement to said abutment.

7. In mechanism o f the character described, the combination with apowerdriven shaft, of a spider secured to said shaft, friction diskssplined to said spider, non-rotatable friction disks alternatelydisposed with respect to the first-mentioned disks, axially movablepressure plates for pressing all of said disks together, centrifugalmeans revolving with said spider and operating on one of said pressureplates, a reversible motor, and means operated by said motor for varyingthe position of the other Y pressure plate.

8. In mechanism of the character described, the combination with arotary shaft, of a friction disk rotatable therewith, a nonrotatablefriction disk, said friction disks being coaxially arranged with respectto said shaft and axially movable with respect thereto, axially movablepressure plates for press- -ing said friction disks together, acentrifugal governor mounted on said shaft for imparting an axialmovement to one of said pressure plates, and a reversible motorconnected to the other of said pressure plates.

9. In mechanism of the character described, the combination with apower-driven shaft, of a spider secured to said shaft, friction diskssplined to said spider, other friction disks respectively interposedbetween the first-mentioned disks, means for holding thesecond-mentioned disks against rotation, an Aabutn'lent for limiting theaxial displacement of said disks, centrifugal levers revolving with saidspider for exerting variable pressure on said disks, a cross headslidable on said shaft and connected to said centrifugal levers, and acompression spring interposed between said spider and cross-head.

l0. In mechanism of the character described, the combination with apower-driven shaft, of a spider secured to said shaft, friction diskssplined to said spider, non-rotatable friction disks alternatelydisposed with respect to the first-mentioned disks, an abutment forlimiting the axial displacement of said disks, centrifugal leverspivoted to said spider, and a pressure ring provided withV axiallypresented pins reciprocable in said spider and in operating engagementwith said centrifugal levers.

11. In mechanism of the character described, the combination with arotary spider, of friction disks splined thereto, nonrotatable frictiondisks alternately arranged with respect to the iirstmenti0ned disks, areeiprocable abutment, a Worm Wheel for re- 10 ciprocating saidabutment, a Worm meshing with said Worm wheel, a reversible motor `forrotating said Worm, an axially movable pressure ring operating inopposition to said abutment, and centrifugally Operated levers pivotallymounted on said spider and engaging said pressure ring.

Signed at New York city, in the county of New York and State of NewYork, this 5th day of April, A. D. 1922.

MILTON T. WESTON.

